Photosensitive polyvinylbutyral lacquer



United States Patent 015cc 3,545,973 PHOTOSENSITIVE POLYVINYLBUTYRALLACQUER Theo Tjalke Boersma, Hendrikes Johannes Veenendaal,

and Hendrikus Cornelis Nicolaas van der Sanden, Emmasingel, Eindhoven,Netherlands, assignors, by mesne assignments, to U.S. PhilipsCorporation, New York, N.Y., a corporation of Delaware No Drawing. FiledApr. 18, 1967, Ser. No. 631,578 Claims priority, applicationNetherlands, Apr. 20, 1966, 6605244 Int. Cl. G03c N66 US. Cl. 9693 2Claims ABSTRACT OF THE DISCLOSURE Photosensitive materials comprising apolyvinylbutyral lacquer and an aliphatic alkaryl, dimethyl ammoniumbichromate. An example is dimethyllaurylbenzyl ammonium bichromate.

The invention relates to the preparation of a photosensitivepolyvinylbutyral lacquer which contains a waterinsolublepolyvinylbutyral resin and a bichromate. Such lacquers are used inphotomechanical processes.

In the applicants prior patent application, application Ser. No.498,144, filed Oct. 19, 1965, now Pat. No. 3,471,294, it is stated thatphotosensitive lacquer of this type may particularly advantageously beprepared by using a water-insoluble or substantially water insolubleorganic bichromate which, however, is readily soluble in solvents inwhich the polyvinylbutyral resin is soluble.

When using these organic bichromates it was found that the dark reactionin lacquer layers on a metal substrate proceeds off more slowly than inlacquers which contain inorganic bichromates.

It has been found that the physical and photomechanical properties ofthe resulting lacquer layers also are less influenced by theclimatological conditions existing while drying the layers.

Thermally stable lacquers, that is to say, lacquers having long potlives, are obtained in particular with organic quaternery ammoniumbichromates of the general formula:

in which n=0, 1, 2 or 3. According to said prior patent application, Rmay be an aliphatic saturated or unsaturated hydrocarbon chain having 6to 18 carbon atoms or an alicyclic ring. If n is smaller than 3, thevarious hydrocarbon radicals R may be ditferent or the same.

Examples of such compounds are dimethyldilauryl ammonium bichromate andtrimethyllauryl ammonium bichromate.

According to the invention, it has been found that improved results areachieved by the use of quaternery ammonium bichromates of the formula:

wherein R is an aliphatic hydrocarbon moiety of 6-18 carbon atomsinclusive and R is alkaryl of 7 to 12 carbon atoms inclusive.

It has been found that these compounds are more soluble in the solventsfor the polyvinylbutyrals than the corresponding quaternery ammoniumbichromates of the prior application. Thus by use of the bichromates ofthe instant case, it is possible to produce lacquers of highersensivity.

In the bichromates of this invention R may be for example, octyl, decyl,dodecyl (lauryl), tetradecyl (myristyl) hexadecyl (cetyl), octadecyl(stearyl).

Patented Dec. 8, 1970 Bichromate: of lacquer Trimethyllaurylammonium 3Dimethyldilaurylammonium 5 Dimethyllaurylbenzylammonium exceeding 5 Thepreparation and the use of a lacquer according to the invention will nowbe described in greater detail with reference to the following example.

EXAMPLE 4 g. of dimethyllaurylbenzyl ammonium bichromate. was added to asolution of 13 g. of polyvinylbutyral (vinyl alcohol contentapproximately 20% by weight, viscosity of a standard solution of 10% byweight of polyvinylbutyral in methanol: cm. at 25 in a mixture of 75mls. of dimethylformamide and mls. of butanone. After the completedissolution of the bichromate, a previously cleaned copper plate wasdipped in this solution in such manner that after drying in air of 40 C.an evenly thick lacquer layer was obtained. This layer was exposed tolight through a template for 1 minute by means of four 125 watt highpressure mercury discharge lamps placed in the corners of a squarehaving sides of 15 cms. at a distance of 50 cms. from the object. Theunexposed parts of the lacquers were then washed away in methanol. Theremaining lacquer pattern may be used as a screening layer for variousetching or electro-deposition processes.

While we have described our invention in connection with specificembodiments and applications, other modifications thereof will bereadily apparent to those skilled in this art without departing from thespirit and scope of the invention as defined in the appended claims.

What we claim is:

1. A photosensitive polyvinylbutyral lacquer containing awater-insoluble polyvinylbutyral resin and an organic quaternaryammomiumbichromate of the formula:

[ 1 2 a)2] a a r wherein R is an aliphatic hydrocarbon chain of 6 to 18carbon atoms and R is aralkyl of 7 to 12 carbon atoms.

2. The photosensitive lacquer of claim 1, whereindimethyllaurylbenzylbichromate is employed.

References Cited UNITED STATES PATENTS 3,471,294 10/ 1969 Boersma et al9693 FOREIGN PATENTS 1,123,642 8/1968 Great Britain 9693 RONALD H.SMITH, Primary Examiner US. Cl. X.R. 9636, 75, 115

